1. Field of the Invention
The present invention relates to a shielded cable with a connector obtained by fitting an end of a shielded cable used to electrically connect electronic instruments with a connector.
2. Related Background Art
Recently, with the improvement and diversification of the functions of electronic instruments, various electronic instruments such as a personal computer, a printer, etc. transmit and receive a large volume of data at a high speed between substrates of an electronic instrument, or between electronic instruments. In this connection, an increasing number of cables with multipin connectors have been used as interfaces. When such cables with multipin connectors are used in transmitting signals between electronic instruments, there often arises the problem about radiation noise and immunity. Thus, a shielded cable obtained by covering a bundle of a plurality of cores with a mesh-shaped shielding member. The shielding member suppresses radiation noise by being electrically connected to a conductive metal housing of the connector fitted to the end of the shielded cable.
In addition, the housing of the substrate side connector of the electronic instrument, which is the opposite side to the connector of the shielded cable is also a conductive metal member, and is electrically connected to the metal housing of the electronic instrument. Thus, with the housing of the shielded cable side connector fitted to the substrate side connector, and both connectors electrically connected, the shielding member of the shielded cable is electrically connected to the housing of the electronic instrument, which is the ground, through the housings of the connectors, thereby suppressing the radiation noise by the shield effect.
However, if the electric connection between the members from the shielding member of the shielded cable to the housing of the substrate side connector of the electronic instrument is incomplete, then the shield characteristic of the radiation noise largely fluctuates, thereby causing the radiation noise.
The first factor of the incomplete electric connection from the shielding member of the shielded cable to the housing of the substrate side connector of the electronic instrument can be a defective electric connection in the fitting portion between the cable side connector and the substrate side connector. Normally, the cable side connector is fitted to the substrate side connector with the fitting portion of the cable side-connector set outside while the fitting portion of the substrate side connector set inside, and with the fitting portion of the cable side connector a little extended. Therefore, the shape of the fitting portion of the cable side connector is likely to be deformed, thereby causing an incomplete connection state between the cable side connector and the substrate side connector after repeated use.
Furthermore, normally, the cable side connector is formed by an outer housing forming the exterior, and an inner housing having a fitting portion of the substrate side connector. Therefore, the second factor of the incomplete electric connection from the shielding member of the shielded cable to the housing of the substrate side connector of the electronic instrument can be a defective electric connection between the outer housing and the inner housing. The unstable state of the electric connection becomes worse by the distortion of the fitting portion of the cable side connector caused when the cable side connector is fitted to the substrate side connector.
In addition, a clamp portion for connecting and clamping to the shield portion of the shielded cable is formed at the back end portion of the outer housing. The clamp portion is formed by an elastic member having a U-shaped section. By reducing its diameter, the circumference of the shield portion of the shielded cable can be clamped. However, since the clamp portion is formed by an elastic member, it is easily deformed, thereby causing an incomplete electric connection between the shielding member provided for the shielded cable and the outer housing, which is the third factor of the incomplete electric connection from the shielding member of the shielded cable to the housing of the substrate side connector of the electronic instrument.
An object of the present invention is to eliminate the first factor of the incomplete electric connection from the shielding member of the shielded cable to the housing of the substrate side connector of an electronic instrument, and ensure and stabilize the electric connection between the fitting portion of the cable side connector and the fitting portion of the substrate side connector, with the cable side connector being fitted to the substrate side connector.
Another object of the present invention is to eliminate the second factor of the incomplete electric connection from the shielding member of the shielded cable to the housing of the substrate side connector of the electronic instrument, and to ensure and stabilize the electric connection between the inner housing and the outer housing of the cable side connector.
A further object of the present invention is to eliminate the first, second, and third factors of the incomplete electric connection from the shielding member of the shielded cable to the housing of the substrate side connector of the electronic instrument and to ensure the electric connection of all members from the shielding member of the shielded cable to the housing of the substrate side connector of the electronic instrument.
To attain the object, the present invention provides a shielded cable with a connector, in which the connector is connected to an end portion of the shielded cable formed by covering a plurality of cores with a shielding member, comprising an inner conductive housing having an electrode portion-provided with a plurality of electrodes connected to a plurality of cores, and having a fitting portion for fitting to a connector which is the opposite side of the connection; and an outer conductive housing combined with the inner housing, and containing the cores exposed from the shielded cable. The outer housing is electrically connected to the shielding member, and is electrically connected to the fitting portion of the inner housing through the conductive connecting portion which is elastically connected to the fitting portion.
Furthermore, according to the present invention, the connecting portion is made of a member different from member of the outer housing.
According to the present invention, the connecting portion has a bent portion vertical to the longitudinal direction of the inner housing, and is connected to the fitting portion of the inner housing by the elasticity of the bent portion.
According to the present invention, the connecting portion is a conductive leaf-spring-like member.
According to the present invention, the connecting portion is formed so as to contact a plurality of portions of the fitting portion of the inner housing.
According to the present invention, the connecting portion has a saw-teeth array.
According to the present invention, the connecting portion has a plurality of convex portions in the longitudinal direction of the inner housing.
Furthermore, according to the present invention, the connecting portion is further provided with a conductive connecting member inserted between the fitting portions of the outer housing and the inner housing.
According to the present invention, the connecting member has a pin array obtained by connecting a plurality of conductive metal pins parallel to each other and being incorporated into one structure.
Furthermore, according to the present invention, the connecting member is a conductive leaf spring.
In addition, according to the present invention, the connecting member is a gasket of conductive rubber.
Furthermore, the present invention is to provide a shielded cable with a connector, in which the connector is connected to an end portion of the shielded cable formed by covering a plurality of cores with a shielding member, comprising: an electrode portion provided with a plurality of electrodes connected to cores; a conductive inner housing having a fitting portion for fitting to a connector which is to be fitted to the connector, and having the electrode portion therein; and a conductive outer housing which is used in combination with the inner housing and containing cores exposed from the shielded cable, wherein the outer housing is designed to have an end portion of the shielding member inner the cable inlet provided at a back of the outer housing, and a conductive clamp portion provided at a back end of the outer housing clamps the shielding member of the shielded cable to electrically connect; and the outer housing is electrically connected to the inner housing through a conductive connecting portion elastically connected to the fitting portion of the inner housing.
Furthermore, according to the present invention, the cable inlet is electrically connected to the shielding member at a number of points.
In addition, according to the present invention, the cable inlet is formed to be a square such that the each side of the square is shorter than the diameter of the shielding member and the cable inlet is electrically connected to the shielding member at a number of points.
Additionally, according to the present invention, the cable inlet is formed such that its diameter is substantially the same in size as the diameter of the shielding member, one, or more projections are provided on the edge of the cable inlet, the cable inlet is electrically connected to the shielding member through the projections.
Furthermore, according to the present invention, the saw-teeth shaped projections are provided on the cable inlet.